Various antibiotics, particularly penicillin, tetracycline, streptomycin and other antimicrobial antibiotics, are employed typically with milk-producing animals, and more particularly in the treatment of mastitis in milk-producing cows. The use of such antibiotics often leads to the product of milk which has been contaminated with such antibiotics, and particularly with penicillin in the more typical situation. Milk contaminated by such antibiotics cannot be sold by law, if the penicillin or other antibiotics are present in a detectable amount. At present, highly contaminated milk would present a fluid of reconditioned, dried-milk product having a detectable level of 0.1 international units per ml of penicillin G in the milk; for example, 0.1 to 0.2 international units (where 0.05 international units are equal to 30 nanograms of the penicillin G per ml). A present standard test for the detection of penicillin in milk is a microbial-inhibition test which does not exceed a sensitivity of approximately 0.01 international units per ml. Thus milk contaminated with penicillin is hazardous and cannot by law be employed in fluid form.
Contaminated fluid milk, when found, is often discarded, or it may be subject to a multiple drying process; that is, dried and redried several times, to recondition the milk and to form a reconditioned dried product. The reconditioned dried product then may be mixed with water to form a liquid, reconditioned-milk composition which also must not have any detectable penicillin or other antibiotics therein. Only relatively low amounts of penicillin in contaminated milk can be accommodated by employing the reconditioning process. Contaminated dried milk may be sold as an animal-feed product or supplement, but demands a very low price, while a liquid, reconditioned-milk composition; that is, a milk composition using the dried, reconditioned-milk powder, without detectable penicillin, may be sold at a much higher price and may be employed for manufacturing various edible food products which contain other ingredients, such as for use in candy, bakery products and the like. Thus highly contaminated fluid milk must be discarded, while fluid milk containing very low levels of penicillin contamination may be reconditioned using a multiple-drying process; however, such a process is both costly and time-consuming and often leads to uncertain results as to whether the dried milk can be prepared without detectable penicillin therein.
Therefore, it would be most desirable to provide for a simple, effective and inexpensive process for the treatment of contaminated milk to remove penicillin and/or other contaminating antibiotics therefrom.